The study is directed to the possible relationship of EB virus to certain lymphomas and chronic diseases. Throat washings from healthy controls and patients with various lymphomas and others with systemic lupus erythematosus will be tested for 1) pharyngeal excretion of EB virus; 2) antibody increases to EB and other viruses; 3) cellular immunity in selected patients as measured by the response of their lymphocytes to viral and non-viral antigens, the determination of T and B cell numbers, and their morphological characteristics under the scanning electron microscope. For comparison, patients with acute infectious mononucleosis will be similarly studied as a model of a primary EBV infection. In vitro morphological and immunological studies of EBV infected lymphocytes in continual culture will be made. BIBLIOGRAPHIC REFERENCES: Black, F.L., Hierholzer, W.J., Pinheiro, deF., Evans, A.S., Woodall, J.P., Opton, E.M., Emmons, J.E., West, B.S., Edsall, G., Downs, W.G. and Wallace, G.D.: Evidence for persistence of infectious agents in human populations. Amer. J. Epid., 100: 230-250, 1975. Evans, A.S., Niederman, J.C., Cenabre, L.C., West, B., and Richards, V.A.: A prospective evaluation of heterophile and Epstein-Barr virus-specific IgM antibody tests in clinical and subclinical infectious mononucleosis: Specificity and sensitivity of the tests and persistence of antibody. J. Inf. Dis., 132: 546-554, 1975.